"It was terrifying," a now-grown Radell said of the president's death. "It was just a convergence of emotions -- of fear, because he was such a protector of the nation and such a leader, and we all loved him. He was a fatherly figure."

Radell's sentiment years later is a common theme in the letters.

"One woman compared the assassination of President Kennedy with the crucifixion," Fitzpatrick said. "She said that 'they killed our Lord and Father, and now they have killed our president and father.'"

Martha Ross, the daughter of a slave, wrote of the closeness she felt with the president and addressed his two children in her letter, saying their father was "my friend."

"You know even those people that didn't like him ... loved him," said Winston Lucky, Ross's grandson. "He was a strong man. My grandmother, she always talked about that he was going to help set this country right."

One letter from a cabdriver ends with a question: "Why, why I'm still asking myself why?" the driver writes.

A month after the president was shot in Dallas, Texas, on Nov. 22, 1963, Jacqueline Kennedy acknowledged the letters.

"All of you who have written to me know how much we loved him, and he would return that love," she said in December.

Kennedy was president from 1961 to 1963. Jacqueline Kennedy died in 1994.

At her funeral, her son summed her up in one sentence: "Love of words, the bonds of home and family, and her spirit of adventure."